Fuel injector



Patented Mar. 10, 1953 2,630,751 FUEL INJECTOR William H. Mashinter,Chicago, Ill., assignor of nineteen per cent to Margery D. McCormick andAlan G. McCormick, both of Chicago, Ill.

Original application May 29, 1944, Serial No- 537,793. Divided and thisapplication November 2, 1945, Serial No. 626,220

8 Claims.

This invention pertains to pump mechanism, injector mechanism oratomizing mechanism adapted to either supply solid liquid or spraycomminuted fluid, or mixtures of fluid and solid.

Fuel injection pumps as heretofore designed commonly include a plungerworking in a cylinder and intermittently actuated to deliver measuredquantities of fuel to the engine. Because of the high fuel pressuresordinarily involved, a very close fit between plunger and cylinder isrequired for successful operation and a leak-proof fit is extremelydiflicult to obtain and impossible to maintain, particularly when usinglight fuels, such as gasoline, having little or no lubricatingproperties.

One object of the present invention is to provide a substantiallyleak-proof fuel injection pump.

Another object is to provide a fuel injection pump that is substantiallyimmune to leakage producing wear.

Another object is to provide an improved bellows type of pump capable ofwithstanding high pressures over long periods of use.

Another object is to combine a bellows type of pump and a fuelin-jectionnozzle into a unitary structure.

Another object is to provide a. fuel injection nozzle having aself-contained bellows type of pump and a loaded discharge valveresponsive to the pressure in the pump.

Another object is to provide a pump fed fuel injection nozzle having aself-cleaning discharge valve. v

Another object is to provide a combined fuel pump and injection nozzle;of improved, simple and inexpensive design.

Another object of the invention is to provide pump mechanism soconstructedand arranged that it may be used to pump solid liquid.

Another object of the invention is to provide a pump for supplying fluidunder pressure and in measured quantities to means for utilizing thesupplied fluid, as where fuel is sprayed into the cylinder of'an engineor where other liquid, such as water, is sprayed into 'such cylinder forpower plied therefrom is controlled by the pressure of the fluiddelivered to the injecting means.

With these and various other objects in view, the invention may consistof certain novel features of construction and operation as will be morefully described and particularly pointed out in the specification,drawings and claims appended hereto.

In the drawings, which illustrate embodiments of the device and whereinlike reference characters are used to designate like parts- Figure 1 isa sectional view of a modified form of pump and nozzle adapted to beactuated by engine cylinder pressure of the-cylinder to be supplied bythe nozzle and wherein electrically controlled throttle venting andcirculating means is provided; and

Figure 2 is a sectional view of a modified form of pump and nozzleadapted to be actuated by electrically controlled means and whereinelectrically controlled throttle venting and circulating means isprovided.

This application is a division of application Serial No. 537,793, filedMay 29, 1944', for Fuel Injector, now Patent No. 2,530,128, November 14,1950.

Referring first of all to the injector illustrated in Figure 1, theinjector is adapted to utilize the compression pressure of the cylinderto which fuel is to be supplied by the injector for the operation of theinjector. The injector comprises a nozzle 284 secured as by threads 286to the housing or casing 288, the upper end of the casing being closedby means of the end head 290. The head 290 is provided with inletfitting 292 adapted to be connected to a suitable source of fuel supply,not shown, said fitting being provided with the spring pressed valve 294seating toward the source of supply.

The end head is provided with the concentric flanges 296 and 298 towhich the upper ends of the outer and inner bellows 300 and 302 aresecured in a leakproof manner, the lower ends of said bellows beingsimilarly secured to the outer and inner concentric flanges 305 and 308of the intermediate movable seal 3l0. The seal 3l0 is provided with theoppositely extending flange M2 to which the upper end of the bellows 314is secured in a leakproof manner, the lower end of said bellows beingsimilarly connected to the lower stationary seal SIB secured between theand is also provided with the exhaust valve opening 320 which in turn isconnected to the source of supply through a fitting, not shown. Theopening 326 is adapted to be closed by means of the valve 322 urgedtoward closed position by means of the spring 324, said valve beingcontrolled by means of the electromagnet 32S operated through suitableconductors 328 by suitable throttle control means, not shown, such as bya rotary controlled switch similar to a distributor, the switch beingrotated by or in accordance with the operation of the engine, but thelength of contact being controlled manually,

The head 2% is also provided with he downwardly extending tube 330'extending to a point adjacent the hottest part of the injector, the tubebeing in communication with the inlet fitting 292. The nozzle isprovided with a spring seat 332 for one end of he spring 33s, the otherend of the spring being seated on the spring seat 33% provided on thevalve stem: 338 and provided with the valve 34!] adapted to seat on thenozzle seat 3 12.

The nozzle is also provided with the bore 3&6 communicating with thevalve bore 366 which in turn communicates with valve stem bore 343,communicating with the chamber 359 formed between the casing 288 andthebellows 3&0. The valve 352 is adapted to close the seat 35 3 of bore:38, the valve being urged toward closed position by means of the spring356 disposed between the seat 358, provided. in the casing 288, and theseat 369 provided on. the flattened valve stem 362. The valve stem 362:extends upwardly and is adapted to be contacted by the movable seal tit,downward movement of the seal. Sit causing valve 352 to be opened.

On the compression stroke, valve 36s is closed and valve 352 is open andcompression pressure will then be introduced tc the chamber 350, causingupward movement of the seal em to elongate the bellows 3M and compressthe bellows 3532, causing a predetermined amount of fuel to be suppliedunder pressure to the valve 34% causing the valve to open and inject apredetermined amount of fuel into the cylinder. This predeterminedamount of fuel is determined by operation of the electromagnet 328 toopen the valve 322, reducing the pressure at the valve 3&0 to permit thespring 334 (and cylinder pressure) to close said valve. Predeterminedupward movement of the seal Sill as limited by the shoulder 32?, willpermit the spring 356 to close the valve 352 for the power stroke and apredetermined portion of the exhaust stroke of the engine. Thecompression pressure in the cylinder is reduced on the exhaust stroke toa predetermined amount, at which time valve 352' will be permitted toopen, equalizing the pressures in the chamber 35% and the cylinder,causing downward movement of the seal 3w by the return of the bellows tonormal position, urging the valve 3-52 to fully open position, at whichtime the injector is in position for repeating the cycle.

In the construction shown in Figure 2, an injector is illustrated whichis not dependent upon compression pressure for its operation so that itmay be timed to inject fuel on the intake stroke of an engine or on thecompression stroke thereof. This injector consists essentially of thenozzle 364 secured as by means of the threads 35% to the housing orcasing 368, the'upper portion of the casing being closed by means of theend head are.

The end head is provided with the inlet fitting 312 adapted to beconnected to a suitable source of supplyand being provided with a springpressed valve 374 closing toward the sourceof supply.

(If: (H:

The head 370 is provided with the electro-magnet 316 connected throughsuitable conductors elt to a throttle control, such as described withrespect to Figure 1, said electro-magnet being adapted to open thespring pressed outlet valve 383 controlling the outlet opening 382 whichis connected back to the source of supply. The spring of said valveurges the valve to closed position.

The head 376 is provided with the depending spaced concentric flanges385 and 356 to which are secured in a leakproof manner the upper ends ofthe outer and inner bellows 383 and 399. The space between the bellowsis vented as through openings 392. The lower ends of the bellows aresimilarly connected to the outer and inner concentric flanges 394 and396, respectively, of the movable seal 358, said seal being urgedupwardly by means of the spring 280, one end of the spring seating onthe seal 398 and the other end of the spring seating on seat 402 of thecasing.

The casing is provided with the electro-magnet fills connected throughsuitable conductors 383 to operating means, as for example, a rotaryswitch operated by the engine and so constructed and arranged that theelectro-magnet is energized any time after injection has ceased, forexample, on the suction stroke up until the time that injection isinitiated, at which time the electromagnet 404 is ole-energized.

The seal 398 is provided with the flange 33 to which the upper end of.the bellows alt is secured in a leakproo-f manner, the lower end of thebellows being similarly secured to the fixed seal M2 secured between thecasing 368 and the nozzle 35%. The head 310 is alos provided withthedownwardly extending tubular member lit in communication with thefitting W2 and extend ing to a point adjacent the nozzle whereby coolfuel is supplied to the hottest part of the injector. The nozzle isprovided with the valve seat litl adapted to be closed by the valve M8,the valve being provided with the stem 428, said stem being providedwith the spring seat 422, for one end of the spring 424, the lower endof the spring being seated on the seat 426 of the nozzle.

In operation of this form of the device the electro-magnet rill-l isenergized at some time after injection has ceased, for example, on thecompression stroke, causing downward movement of the eal 398, elongatingbellows 39d and compressing bellows till and fuel is supplied throughthe fitting 312 to the inside of bellows M8, 399, and spring 490 iscompressed. At a suitable time prior to the time the piston of thecylinder has completed its compression stroke, the electromagnet $64 islie-energized, permitting spring 506 to move the seal 408' upwardly,causing fuel under pressure to besu'pplied to the valve M8 and injectedinto the cylinder. The amount of fuel is regulated by energizingelective-magnet 3T6 which will open valve'ilall to terminate injection.The pumping stroke of the bellows, as determined by the movement of theseal 398 is always the same, regardless of the speed of the motor as itmoves from the lowermost position when the electro-ma'gnet' 404- isenergized. to its uppermost position when magnetic! is lie-energized,against the stop 405' formed in the body of the upper electro-magnet butthe amount of fuel that is injected is controlled by the valve 38! Thepumping stroke, then, of this device is governed not by the speedottl-ie engine, but by the capacity of the springd'flll, Y

Comparison of load-speed control of injectors of known type and thoseillustrated herein In order to obtain the degree of control over theratio of air and fuel (needed for optimum economy and satisfactoryperformance) that is introduced into an engine cylinder, it is essentialthat the quantity of fuel per injection be maintained at a fixed ratiowith respect to the quantity of air inducted per suction stroke of theengine cylinder.

In a naturally aspirated (not supercharged) internal combustion enginethe quantity of air inducted per suction stroke of the engine decreaseswith increases in engine speed for each and every air throttle positionaccording to the volumetric-efficiency curve (breathing rate) of theengine.

Thus it is evident that if a constant ratio of air and fuel is to bemaintained at all times and under all conditions of speeds and loads(loadspeed control), the speed-delivery characteristic of the injectionsystem should conform to the same general form as thevolumetricefliciency curve of the engine.

In an engine operating on the Otto cycle (such as a gasolinespark-ignition engine) it is necessary to control the air-chargeinducted by a throttle control over the air as well as the fuelintroduced to the engine. Thus there is a family ofvolumetric-efficiency curves (one curve for each throttle position). Inthe diesel engine, as no air throttle is provided, there is only onevolumetric-efficiency curve for the air charge inducted (full throttle).

All commercial forms of fuel injection pumps now in use utilize aplunger-barrel combination, as a pumping means. The type of injectionpump in most extensive use at the present time, employs a portcontrolled by-pass, with an undercut section of the plunger as the slidevalve means for controlling the porting of this by-pass ort in order tocontrol the quantity of fuel delivered by the pump.

The following formula expresses the leakage rate of the above type ofplunger-barrel pumps.

Leakage rate a l. c is a constant.

2. l is the mean clearance between the barrel lapped portion between theplunger and the barrel. I

6. a is the viscosity of the liquid being pumped.

'7. L is the length of the lapped fit.

Due to the leakage condition it is necessary in this piston type of pumpto provide a cam profile with a rate of lift sufficient to overcome thisleakage at slow speeds, especially cranking speeds as are encounteredwhen cold-starting the engine. As a result, the speed-deliverycharacteristics of this type of pump tend to fall off at slow speeds(when the time for leakage is the greatest) and also at high speeds(when the pressure causing leakage is the greatest).

As a result of the above conditions the tendency at the higher throttlerack settings is to result in speed-delivery characteristics, which falloff much more rapidly with increasing engine speed than the volumetricefficiency of the engine does, and results in the failure to maintainthe air to fuel ratio.

the curve has an exactly opposite slope. Thiscondition former.

is equally as undesirable as the:

Thus it may be seen that as the quantity per injection at the higherthrottle conditions falls off too rapidly due to leakage, there Will bea speed at which delivery will fall below the quantities necessary, andresult in a, definite limit to engine speeds that can be obtained. Thiscondition is especially bad when the high pressure pump and nozzle areseparated by a delivery tube (due to adverse pressure wavecharacteristics).

In the modifications shown herein the effect of leakage is eliminated bythe use of a hermetically sealed pumping element, and a unitaryconstruction is employed in order to overcome the disadvantage of apump-delivery-tube-nozzle combination. The absence of leakage makespossible the use without adverse effects of whatever a shape isnecessary in'order that the fenced-delivery characteristics of theinjector will conform exactly to the volumetric-efficiency curve of theengine. Thus in the modifications herein, it is possible to obtaincomplete and automatic loadspeed control. v

The injectors shown herein may readily be operated as pusher or sumppumps located at the source of supply and supplying fuel to in jectorsor a carburetor, also they may be used to inject liquid, as water, intothe cylinders (or manifold) for anti-detonating purposes.

It is to be understood that I do not wish to be limited. by the exactembodiments of the device shown, which are merely by way of illustrationand not limitation as various and other forms of the device will, ofcourse, be apparent to those skilled in the art without departing fromthe spirit of the invention or the scope of the claims.

I claim:

1. In an injector, the combination of a housin having a top end closureat one end and a discharge opening at the other, large'and smalldiameter communicating chambers in said housing, an outwardly openingdischarge valve in said opening, resilient means urging said valve toclosed position, a fixed seal in said small diameter chamber adjacentsaid valve, an intermediate seal in said large diameter chamber, abellows in said small diameter chamber having the ends thereof connectedto said seals, an inner bellows connected to said intermediate seal andto said top enclosure, an outer bellows connected to said intermediateseal and top end closure, vents in said closure between last namedbellows, means extending through said closure and into said. firstbellows for supplying fuel thereto adjacent said valve, an exhaust valvein said second bellows for returning fuel and vapor to the source ofsupply, electro-magnetic means for controlling said last valve. a valvein said housing controlled by said intermediate seal for permittingexterior pressure to be introduced to said housing to 'pulsate the thirdbellows to cause pulsationsof one of the other bellows to supply fuelthrough said discharge opening.

2. In an injector, the combination of a housing, a valve openingoutwardly of said housing, resilient means urging said valve towardclosed position, a bellows secured at one end to said housing adjacentsaid valve, an intermediate seal secured to the other end of saidbellows, a second bellowssecured at; oneend to, said seal and at theother end tosaid using, an outlet from within said second bellgwsnormally closed valve for said. out et; lec r m e c means for 5616*tively opening said valve, means for Supplying fluid to be ejected tosaid first named bellows, and means for moving said seal to therebypulsate said bellows.

In an injector, the combination of a housin having a top end closure atone end and a discharge opening at the other, large and small diametercommunicating chambers in said housing, a fixed seal insaid smalldiameter chamber adjacent said opening, an intermediate seal n saidlarge diameter chamber, a bellows in said small diameter chamber havingthe end thereof connected to said seals, an inner bellows connected tosaid intermediate seal and to said top end closure, an outer bellowsconnected to said intermediate seal and top end closure, vent in saidclosure between last named bellows, means extending through said closureand into said fi bellows for supplying-fluid thereto adjacent saidopening, an exhaust valve in said second bellows for returning fluid andvapor to the source of supply, electro-Inagnetic means for controllingsaid last valve, a valve in said housing controlled by said intermediateseal for permitting pressure to be supplied in a pulsating manner tosaid housing to pulsate'the third bellows to cause pulsations of one ofthe otherbellows to supply fluid through said opening.

4. In an injector, the combination of hoursing having a, dischargeopening at one end, a bellows secured at one end to said housin jacentsaid opening, an intermediate seal to the other end of said bellows, asecond bellows secured at one end to said seal and at the other end tosaid housing, an outlet from within said second bellows, a normallyclosed valve for said.

intermediate seal secured to the other end of said bellows, a secondbellowssecnred at one end to said seal and at the other end to saidhousing, an outlet from within said second bellows, a normally closedvalve for said outlet, electro-magnetic means for selectively openingsaid valve,

.eans for s ngs-plying fluid to be elected to said first named bellows,and means for moving said seal to thereby pulsate said bellows.

n an in e t r. the omb nat on of a 0 3- ing having a discharge openingat one end, a bellows secured at one end to said housing adiacent saidopening, an intermediate seal secured to the other end of said bellows,asecond bellows secured at one end to said seal and at the other d: t ad hou ing evident r W hin ai second bellows, a, normally closed. valvefor said outlet, electromagnetic means for selectively opening saidvalve, means for supplying fluid to be ejected to said first namedbellows, and means including an electromagnet adapted to be selectivelyenergized and tie-energized for moving said seal to thereby pulsate saidbellows.

'7. In an injector, the combination of a housing having a dischargeopening at one end, a bellows secured at on end to said housing adjacentsaid opening, an intermediate seal secured to the other end of saidbellows, a second bellows secured at one end tosaid seal and at theother end to said housing, an outlet from within said second bellows, anormally closed valve for said outlet, electro-magnetic means forselectively opening said valve, means for supplying fluid to be ejectedto said f rst named bellows, and means for moving said seal to therebypulsate said bellows. said means including a passage for com municatingfluid pulsations to said seal, and a valve for controllingsaid lastnamed means, said valve being controlled by said seal.

In an iniectonthe combination of a housin having a. top end closureatone end and a discharge opening at the other, large and small diametercommunicating chambers in said housing, a discharge valve for saidopening, resilient means in in said valve to closed position, a seal insaid large diameter chamber, a bellows in said small diameter chamberhaving one end connetted to said housing and the other end connected tosaid seal, an inner bellows connected to said seal and to said top endclosure, an outer bellows connected to said seal and top end closure,vents in saidclosure between said last named. beliows, meansextendingthrough said closure into said first bellows for "supplyingfuel the"eto adjacent said valve, an exhaust valve in second, bellowsfor returning fuel and vapor to the source of supply, means forcontrolling said last valve, and means for moving said seal to therebypulsate said bellows.

WILLIAM H. MASI-IINTER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,162,789 Loane, Jr. Dec. 7, 19151,425,191 Garbarini Aug. 8, 1922 1,455,628 Leroy May 15, 1923 1,856,852Palisca May 3, 1932 1,976,415 Scott Got. 9, 193% 2,046,491 Scott July'7, 1936 2,106,789 Boyd j Feb. 1, 1938 2,180,123 Stanclifie Nov. 14,1939 2,389,492 Edwards Nov. 20, 1945 FOREIGN- PATENTS Number CountryDate 264,'I87 Italy May 11,1929

